Non-slewing luffing crane



June 24, 1969 A. A. 5. HAINES NON-SLEWING LUFFING CRANE Sheet Filed July 19, 1967 June 24, 1969 A. A. 5. HAINES NON-SLEWING LUFFING CRANE Sheet Filed July 19, 1967 June 24, 1969 5. HAINES 3,451,559

uou-snnwme LUFFING CRANE FiledJuly 19, 1967 Sheet 3 of 4 United States Patent 3,451,559 NON-SLEWING LUFFING CRANE Avery Alfred Simpson Haines, 8 Glenn Ave., Mosman Park, Western Australia, Australia Filed July '19, 1967, Ser. No. 654,574 Claims priority, application Australia, Aug. 25, 1966, 10,230/66; Sept. 13, 1966, 11,021/66 Int. Cl. B66c 23/06 US. Cl. 212--8 Claims ABSTRACT OF THE DISCLOSURE Crane with a jib mounted for pivotal movement, from side to side in a vertical plane, and a lufiing arm pivoted on the jib, for rotation in a vertical plane parallel to the plane of movement of the jib, the pivot point on the lufiing arm being chosen so that its working end moves in a substantially horizontal line as the jib moves from side to side.

This invention relates to a non-slewing luffing crane wherein the load to be hoisted is lifted from one position and is moved directly to be set down in another position.

Many crane jibs have a slewing motion about a central vertical pivot which involves the use of heavy tail counterweights. The use of such counterweights involves the use of more power to move the jib. Also, the speed at which these known crane jibs may be rotated about the vertical axis is limited in order to avoid high centrifugal forces which tend to throw the load outwards from the center and create instability. A jib of this type loaded to the point of over-balance when stationary would certainly over-balance when slewed. Furthermore, the load hanging from the hoist rope of a slewing jib does not move directly from one point to another but along the arc of a circle, which is obviously not along the shortest path.

The object of this invention therefore is to provide a crane which does not have the above disadvantages, is inexpensive and which will move loads faster and at a lower cost than previously used cranes.

A non-slewing luffing crane is thus provided, according to the invention, which has a jib mounted adjacent its lower end on a supporting frame, for pivotal movement from side to side in a substantially vertical plane, with a lufling arm pivoted on the upper end of the jib, for rotation in a substantially vertical plane parallel to the plane of movement of the jib, with a restraining means pivotally connected at one end thereof to one end of the lufiing arm, the other end of the restraining means being capable of pivotal movement on the supporting frame. The intermediate pivot point of the luffing arm is so chosen that the other end of the arm moves along a substantially straight horizontal line as the jib moves from side to side.

According to another feature, the restraining means is in the form of a substantially triangular yoke member, the base of which has a pair of recesses adapted' to engage respective roller members mounted on the frame to permit the pivotal movement on said frame.

The various objects, features and attendant advantages of the inventive luffing crane will become (more apparent from the following description of a preferred, exemplary embodiment, when considered in conjunction with the accompanying drawings, wherein FIG. 1 is a somewhat schematic front elevation of a preferred form of the inventive non-slewing lulfing crane; FIG. 2 is a side elevation of the crane of FIG. 1, shown with a different relative position of some parts; FIG. 3 is a front elevation of a spreader arm used in "ice the crane to eliminate twisting of the hoist rope, and a multi-handling bridge;

FIG. 4 is a plan view of FIG. 3, with the bridge only schematically shown;

FIG. 5 is a side elevation of a modified embodiment of a lufi'ing arm, somewhat similar to FIG. 2; and

FIG. 6 is a front elevation of FIG. 5, corresponding to portions of FIG. 1, with the modification included.

The numerals in the drawings denote, as usual, structural crane features or parts, while the numerals represent points, lines or dimensions. Since a structural part, a hoist rope 21, is shown in broken lines, all the lines denoting movement paths, etc. are shown in dot-dash fashion.

With reference to FIGS. 1 and 2, a base frame 1 of the crane stands on four legs 2. A traversing gear 1a is shown on rails 2a, in broken lines, under the legs 2 to illustrate an exemplary, conventional manner in which the crane may be mounted, but this gear is not included in the invention.

The main base hinge of the crane consists of a torque tube 8 mounted near each end in bearings 14, 1 5 which are fixed to the base frame 1 so that the torque tube 8 is free to rotate about a substantially horizontal center line.

The jib of the crane is shown as a column divided into two legs 12 which are fixed together and secured to the front end of torque tube 8. A hoist-rope pulley block 20 is mounted in the lower end of the jib 12. A hollow lufiing-arm pivot 25 is fixed to the top of the jib and projects both to the front and to the rear.

A luffing arm 29 with a crank arm 28 fixed to it is pivoted on bearings 24, 26, and a thrust bearing is mounted within bearing 24 to bear against the end of pivot arm 25 and take the thrust from the hoist rope 21, mentioned before, where the latter passes over a pulley 23 on arm 29.

A pulley 22 is mounted in the top of the jib 12 so that hoist rope 21 is substantially coaxial with the hollow center of pivot 25 where the rope 21 passes between pulleys 23, 22.

A yoke 4, 9, 10, triangular in shape, is hung at the top from a bearing 27 pivoted on the extremity of lufiing crank arm 28. Yoke legs 9, 10 are fixed together at the top as well as to the extremities of yoke base 4.

A girdle 13 is fixed to and near the top of the jib legs 12 in front and is passes clear around yoke 4, 9, 10. From the rear of girdle 13, two back stays are fixed at the top, and at the bottom they are secured to the rear end of torque tube 8.

A machinery cradle 17 is underslung from torque tube 8 through an opening in base frame 1.

A counterweight 16 is fixed to therear extremity of torque tube 8, and designed to counterbalance the dead weight of the moving mechanism so that it hinges and swings freely about the center of bearings 14, 15.

Twin side stays welded to base frame 1 sand vertically on two twin legs 3 which are connected by horizontal members at the top, as illustrated, and stiffened by two twin stays 5. These also brace the base frame 1 against the loading from torque tube bearing 14. At the top of these twin side stays 5, rollers 6, 7 are mounted on pins fixed between the stays. Yoke base 4 has recesses 4a near the inner ends, which are fitted to engage around rollers 6, 7.

At the outer or lower end of the lulfing arm 29 two pulleys 30, 31 are fixed to a beam portion 34 so that hoist rope 21 passes between them and along the center of arm 29.

A toothed rack 18, in the form of the segment of a circle, is underslung and fixed to base frame 1, concentric with the center of torque tube 8 and with bearings 14, 15. A toothed pinion 19 mounted between cradle 17 and counterweight 16 engages with rack 18, and is powered, as schematically shown at 19a, and controlled in a conventional manner to actuate the movement of the jib assembly 12 from side to side.

A hoist winch 21' (dotted or broken) is mounted in cradle 17 so that hoist rope 21 may be wound around the winch drum.

The movements and functions of the crane parts are further illustrated by reference to the afore-mentioned letters which appear in FIGS. 1 and 2.

Point A represents the center of bearing 27. Point B represents the center of bearings 24, 26. Point C represents the point between pulleys, 30, 31. Finally, point D represents the center of bearings 14, 15.

Line W represents the distance between the centers of rollers 6, 7. Lines X and Y represent the distances between the centers of respective rollers 7 and 6, on the one hand, and bearing 27, on the other, when the jib 12 and the lutting arm 29 stand vertically. Radii X, Y are equal in length. Finally, line Z represents the distance between any position of points B and D.

FIG. 1 shows the jib 12 reaching to one extremity on the right hand of the observer. As the jib 12 is moved from this position towards the left, point B moves along the arc of a circle, shown by line B, with radius Z, about point D; and point A at the same time moves along the arc of a circle, with radius X, about the center of roller 7 until it reaches a position vertically above point D, from where point A moves on a similar arc, with radius Y, about roller 6 until it reaches the left-hand extremity so that the locus of point A is represented by the composite line (with relatively heavy dots) running between points C, A, A, A and C again.

Furthermore, during the leftward movement of jib 12, base 4 of yoke 4, 9, rotates on roller 7 while the jib 12 is to the right of the center, and on roller 6 while the jib is left of center. The locus of point C is represented by an almost level line (with small dots) between points C, C and C. This locus may be given any desired characteristics by the selection of suitable relationships between the respective pivot centers A to D and the radii W to Z. Also during the leftward jib movement, the hoist rope 21 changes from rotating about pulley 31 to pulley as it passes across the center of the crane (above point D).

The arrangement of all the crane parts ensures that the dead weight of the moving mechanism is balanced about point D by counterweight 16 at all times, and any load is automatically balanced by the pull of yoke 4, 9, 10. Any further tendency for over-turning of the base 1, plus necessary safety margins, may be counterbalanced by placing additional weights in the bottom of the base legs 2, and thus provide an overall low center of gravity.

Accessories which may be included in the inventive, as well as in any particular other crane design are illustrated by FIGS. 3 and 4 which show how the hoist rope 21 may be prevented from twisting. This arrangement gives the lifting tackle a mechanical advantage.

An anti-twisting spreader arm 34a, constituting the afore-mentioned beam portion (34 in FIG. 1), is pivoted about point C on a pivot 32 projecting from the outer or lower end of lufiing arm 29. The afore-mentioned pulley 30 is housed in spreader arm 34a to clear pivot 32 so that hoist rope 21 may pass between them. In this case, the second pulley is placed as shown by 31a on the extremity of spreader arm 34a.

Hoist rope 21 passes over pulley 31a, thence around a further pulley or block 36, freely suspended on rope 21, and over a rounded groove in the opposite end of spreader arm 34a, terminating in a rope fastener 35. This provides the hoist rope with a mechanical advantage of two. By placing additional sheaves in pulleys 31a, 36 and still another pulley 33, and guiding rope 21 around them, the mechanical advantage may be raised by multiples of two.

A single load may be engaged by attachment to suspended pulley block 36, but if it is desired to handle more than one load of equal or near equal weight simultaneously, a bridge 38 may be slung from a pivot 37 on block 36, and shackles or hooks 39 provided. This bridge 38 may be placed transversely to the side lufiing movement of arm 29, as shown dotted in FIG. 4.

The modified embodiment shown in FIGS. 5 and 6 has been devised for handling multiple crane loads which may vary in overall dimensions and weight. For example, a crane of this description could be designed to handle a container 24' by 8 by 8', weighing twenty-one tons, or three containers simultaneously, each 8' by 8 by 8' but not necessarily of equal weight, say five tons, nine tons and seven tons; or two containers, one being 16 by 8' by 8 and the other 8' by 8' by 8'.

In this embodiment the crane is provided with a winch drum which accommodates two separate but similar hoist ropes 21a and 21b, one around each end of the drum (not shown), so that both ropes are wound in or paid out at the same rate simultaneously. The outer or lower end of a modified luffing arm 29a, 29b forks into two separate arms, and one of the two hoist ropes is led down each of the two arms, to support the ends of a cradle 43 suspended vertically below so that the cradle hangs horizontally from front to rear.

More specifically, a torque tube 8a is inserted as a major horizontal member to resist the torsion between the inner or upper crank arm 28 and the outer or lower divided arm 29a, 29b, and stitfeners 45 are added to re sist bending moment. Bearings 24a, 26b are attached under torque tube 8a and they provide a hollow pivot on top of jib 12 (broken away) so that the hoist ropes 21a, 21b pass around respective pulleys 22a, 22b, then through a hollow tube connected to lower arm 29b.

Both hoist ropes continue horizontally and pass around twin pulleys 23a, 23b, and from this point the path of the twin ropes divides. Hoist rope 21a passes vertically down arm 29a and around an idler pulley 30a, thence around a pully block system 41a, 42a, while hoist rope 21b passes from pulley 23b around idlers 23c, 30b, and thence around pulley blocks 41b, 42b.

Pulley assemblies 41, 42 (including elements 41a, 41b and 42a, 42b) need not necessarily be installed in any particular design since each hoist rope could be arranged to pass between a pair of pulleys, e.g. 30 and 31, as shown in FIGS. 1 and 2, and the ropes could then be directly shackled to the afore-mentioned cradle 43.

FIGS. 5 and 6 are drawn to show a specific loading attachment, and how the hoist ropes may be given a mechanical advantage over the weight supported by cradle 43. Lift points 44 are fixed to the underside of cradle 43 to which any desired additional lifting equipment may be shackled.

If the horizontal distance between the centers of yoke legs 9, 10 (see FIG. 5) and the center of jib 12 is represented by letter Q, and the horizontal distance from the center of jib 12 to a vertical line halfway between arms 29a, 29b is represented by letter P, then the best proportion of Q to P is as that of distance A-B to distance B-C, to ensure that the resultant downward force on top of jib 12 would always be in the center of jib '12 when the center of gravity of all loadings fell midway between luffing arms 29a, 29b or, to the center of cradle 43. Any departure of the load center from this midway point would create eccentric loading on jib 12.

The foregoing disclosure realtives only to a preferred, exemplary embodiment of the inventive luffing crane, and the invention is intended to include all changes and modifications of the example described.

What I claim is:

1. A non-slewing luffing crane comprising a supporting frame, a jib mounted adjacent its lower end on said frame about a substantially horizontal axis for pivotal movement from side to side in a substantially vertical plane,

a side lufiing arm pivoted on the upper end of said jib about a point intermediate its ends for rotation in a substantially vertical plane parallel to the plane of movement of said jib, and restraining means pivotally connected at one end thereof to one end of said lufling arm, the other end of said restraining means being capable of pivotal movement on said frame, the intermediate pivot point on said lufiing arm being chosen so that the other end of said lufiing arm is capable of moving along a substantially straight horizontal line as said jib moves from side to side, said restraining means, said jib, and a portion of said lufling arm between said one end thereof and said intermediate pivot point thereon constituting a trapezial linkage having a fixed pivot point in said horizontal axis at said lower end of the jib, two movable pivot points at said one end and at said intermediate pivot point of the lufling arm, as well as a fourth floating pivot point which is gradually transferred between spaced-apart portions of said other end of the restraining means as said jib moves from side to side, said fixed pivot point being at a level below said floating pivot point.

2. A non-slewing luffing crane comprising a supporting frame, a jib mounted adjacent its lower end on said frame about a substantially horizontal axis for pivotal movement from side to side in a substantially vertical plane, a side lufiing arm pivoted on the upper end of said jib about a point intermediate its ends for rotation in a substantially vertical plane parallel to the plane of movement of said jib, and restraining means pivotally connected at one end thereof to one end of said lufiing arm, the other end of said restraining means being capable of pivotal movement on said frame, the intermediate pivot point on said luffing arm being chosen so that the other end of said luffing arm is capable of moving along a substantially straight horizontal line as said jib moves from side to side, wherein said restraining means includes a triangular yoke member pivoted about its apex on said one end of the lufling arm, the base of said yoke member being pivotable on said frame and having a pair of recesses provided one adjacent each of the inner ends of said base, said recesses being adapted to engage one of a pair of roller members mounted on said frame to permit said pivotal movement of the restraining means on said frame.

3. The lufiing crane as defined in claim 1, wherein the dead weight of all moving mechanisms of the crane is counterbalanced by a counterweight attached to said horizontal axis.

-4. The luffing crane as defined in claim 1, further comprising an anti-twisting spreader arm constituted by a beam suspended substantially at its center from said other end of the lufiing arm, said beam having a pair of pulleys one mounted at each end thereof, and a further pulley mounted immediately above its central suspension point, for the passage of at least one hoist rope around at least two of said pulleys.

5. The lufling crane as defined in claim 4, further comprising a load pulley block suspended on said rope be neath said spreader arm, said rope passing around said further pulley, around one pulley in said pair and down to said pulley block, and then back to the opposite one of said pairs of pulleys.

6. A non-slewing luffing crane comprising a supporting frame, a jib mounted adjacent its lower end on said frame about a substantially horizontal axis for pivotal movement from side to side in a substantially vertical plane, a side lufiing arm pivoted on the upper end of said jib about a point intermediate its ends for rotation in a substantially vertical plane parallel to the plane of movement of said jib, and restraining means pivotally connected at one end thereof to one end of said lutfing arm, the other end of said restraining means being capable of pivotal movement on said frame, the intermediate pivot point on said lufiing arm being chosen so that the other end of said luffing arm is capable of moving along a substantially straight horizontal line as said jib moves from side to side, wherein said lufiing arm is provided with an upper cranked portion which extends over and to the rear of said jib to the pivot point of said restraining means while a lower portion of said luffing arm extends forwardly of said jib and divides into two downwardly directed parallel arms each adapted to move in substantially parallel vertical planes, parallel to said plane of movement of the jib.

7. The lutfing crane as defined in claim 6, further comprising pulleys on each of said parallel arms, adapted to receive two separate hoist ropes each passing down one of said parallel arms to a loading attachment suspended on said ropes beneath said parallel arms.

8. The lutfing crane as defined in claim 1, further comprising a beam portion secured to said other end of the lutfing arm, and a pair of pulleys mounted on said beam portion for guiding of a hoist rope, the weight of the load carried by said rope resting alternately on one of said pulleys as said jib moves from side to side.

9. The lufiing crane as defined in claim 8, further comprising at least one further pulley disposed in the pivotal axis of said luffing arm, and an additional pulley secured to said lower end of the jib beyond said pivotal axis of the latter, for guiding said rope in an uninterrupted and uniform manner in all positions and during all movements of the crane.

10. The lufiing crane as defined in claim 9, further comprising machinery cradle means supported by and movable with said horizontal axis of the jib, drive means on said cradle means and means associated with said drive means for moving said jib from side to side, and hoist winch means for said rope, substantially at the level of said additional pulley, said drive means, said moving means and said winch means being atached to and movable with said cradle means.

References Cited UNITED STATES PATENTS 2,394,217 2/1946 Tom 21259 2,41 1,022.- 11/1946' Botnick 212-9 3,353,687 11/1967 Thomson 21258 3,369,671 2/1968 Yasukouchi 212-59 FOREIGN PATENTS 598,157 6/1934 Germany.

651,197 10/ 1937 Germany.

266,662 8/ 1964- Netherlands.

EDWARD A. SROKA, Primary Examiner. H. C. HO RNSBY, Assistant Examiner.

US. Cl. X.'R. 21249 

